Communication control method in mobile communication system and base station used therefor

ABSTRACT

In the case where a PDSCH is transmitted by only one specific base station and a DPCH is simultaneously transmitted by a plurality of base stations while controlling a transmitting power of the PDSCH according to the DPCH, an optimum value of a power ratio between the PDSCH and the DPCH according to a position of a mobile station is optimized, and the receiving quality of the PDSCH at a fixed level regardless of the position of the mobile station on the soft handover is maintained to be constant. In a specific base station, a value of a ratio between the transmitting power of the PDSCH and that of the DPCH that is a dedicated channel is controlled to be optimized according to the position of the mobile station on the soft handover so that it becomes the ratio determined based on a measured value of a received power of a shared channel or the dedicated channel of a soft handover base station in the mobile station. To be more specific, the mobile station notifies the specific base station of these measuring results, and the specific base station notified thereof multiplies by a coefficient determined based thereon the transmitting power of the DPCH that is the dedicated channel transmitted by the base station itself and transmits it.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a communication control methodin a mobile communication system and a base station and a program recordmedium used therefor, and in particular, to the communication controlmethod of a channel from the base station to a mobile station on softhandover in a CDMA (Code Portion Multiple Access) cellular mobile radiocommunication system.

[0003] 2. Description of the Prior Art

[0004] One of the cellular mobile communication systems is an HSDPA(High Speed Downlink Packet Access) mode, which is a technology fortransmitting packeted data by using a high-speed downlink shared channel(downlink-specific) called HS-PDSCH (High Speed-Physical Downlink SharedChannel) in the case of transmitting to a mobile station large amountsof data (such as the data of a static image and a dynamic image) from acommunication network via a base station. It is a mode wherein, in thecase where the large amounts of data must be simultaneously transmittedto a plurality of mobile stations, this high-speed downlink sharedchannel called HS-PDSCH is shared time-wise (time sharing) to use thisone high-speed channel by sharing.

[0005] When the mobile station approaches a boundary of a cell in such acellular mobile communication system in the HSDPA mode, the mobilestation is in a state capable of communication by setting up channelswith a plurality of base stations having the cells near this boundary astheir service areas, which is called a soft handover state. At the timeof this soft handover, for example, channels are connected between acertain mobile station (MS) 10 and two base stations (BS) 1 and 2 asshown in FIG. 1.

[0006] As for these channels, there are two types as shown in FIG. 1,where one type is a downlink-specific common pilot channel called CPICH(Common Pilot Channel), indicated as a CPICH 1 and a CPICH 2corresponding to the base stations 1 and 2 respectively. In addition,the other type is a dedicated (physical) channel for uplink/downlinkcalled DPCH (Dedicated Physical Channel) and includes variouscommunication data such as control information and voice. It is alsoindicated as a DPCH 1 and a DPCH 2 corresponding to the base stations 1and 2 in FIG. 1. Moreover, in FIG. 1, a PDSCH is the above-mentionedlarge-capacity data channel, which is a downlink-specific shared datachannel.

[0007] Moreover, definitions of such various channels are disclosed inthe 3GPP (3rd Generation Partnership Project) SpecificationsTS25.211V3.0.0 (1999-10).

[0008] It adopts a method wherein, on the soft handover, a plurality ofbase stations 1 and 2 simultaneously transmit the DPCH to a mobilestation 10, and the PDSCH that is the data channel is transmitted byjust one base station (only the base stations 1 in FIG. 1) so as tocontrol transmitting power of this PDSCH in accordance with the DPCH,which is disclosed in the 3GPP Report TR25.841V4.0.0 (2000-12).

[0009] According to this report, transmitting power P_(PDSCH) from thebase station of the PDSCH is determined as follows.

P _(PDSCH) =P _(DPCH1) ·A·C  (1)

[0010] Here, the transmitting power of the DPCH1 is P_(DPCH1), and A isa constant and selected as A=1 for instance. And C is defined asfollows.

P_(CPICH1)>P_(CPICH2)

[0011] In this case, C=C_(primary) (=2 to 3 dB), and if

P_(CPICH1)<P_(CPICH2)

[0012] it is C=C_(nonprimary) (=4 to 6 dB). In addition, P_(CPICH1) andP_(CPICH2) are the received power of the CPICH 1 and CPICH 2 in themobile station.

[0013] In another mobile communication system for performing datacommunication from the base station to the mobile station by using thePDSCH, the transmitting power of this PDSCH is not controlled but isfixed, and instead, it is possible to select a plurality of transmissionmodes of different modulating methods or encoding methods. As for themodulating methods, there are QPSK (Quadrature Phase Shift Keying)capable of transmitting 2 bits (4 values) by 1 symbol, 16 QAM (16Quadrature Amplitude Modulation) capable of transmitting 4 bits (16values) by 1 symbol, 64 QAM (64 Quadrature Amplitude Modulation) capableof transmitting 6 bits (64 values) by 1 symbol and soon. In addition, asfor the encoding methods, there are convolutional encoding of anencoding ratio 1/2 for performing encoding by 2 bits per informationbit, the convolutional encoding of an encoding ratio 1/2 for performingencoding by 3 bits per information bit and so on.

[0014]FIG. 11 shows an example of selection of the transmission modes ofdifferent modulating methods. In FIG. 11, for instance, the transmissionmode is selected so that, a distant from a base station 51 to a mobilestation 52 is shorter, a transmitting speed becomes to be faster. To bemore specific, the base station 51 selects the transmission modes of 64QAM, 16 QAM and QPSK in increasing order of distance to the mobilestation 52.

[0015] While the DPCH is used together with the PDSCH in order totransmit and receive control information on the data transmission by thePDSCH, there is a method in the past, as that of selecting theabove-mentioned transmission modes of 64 QAM, 16 QAM and QPSK, wherein arange of the transmitting power in the base station of the DPCH of thedownlink is determined in advance so as to select the transmission modeaccording to that transmitting power.

[0016] In this case, the mobile station measures receiving quality ofthe DPCH from the base station, compares the measured value to areference value, and notifies the base station of increase or decreasein the transmitting power of the DPCH so that the measured value becomesclose to the reference value. The base station increases or decreasesthe transmitting power of the DPCH according to that notification, andalso selects the transmission mode according to the transmitting powerset up by the increase or decrease. For instance, as shown in FIG. 12,it selects the transmission modes of the 64 QAM, 16 QAM and QPSK inincreasing order of the transmitting power to be set up.

[0017] As for the method of determining the transmitting power of thePDSCH shown in the above-mentioned equation (1), it is a two-stepcontrol method wherein the transmitting power of the PDSCH is determinedby rendering the C of the equation (1) as C_(primary) if, of a pluralityof base stations in the soft handover state, the base station setting upthe PDSCH is one having higher received power of the CPICH in the mobilestation (Primary), and by rendering the C as C_(non-primary) otherwise,resulting in a problem that continuous and elaborate control cannot beexerted. To be more specific, there is a fault that it is not possibleto maintain the receiving quality of the PDSCH at a fixed levelregardless of a position of the mobile station 10 on the soft handover.

SUMMARY OF THE INVENTION

[0018] An object of the present invention is to provide thecommunication control method in the mobile communication system and thebase station and a record medium used therefor, wherein, in the casewhere the PDSCH is transmitted by one specific base station and the DPCHis simultaneously transmitted by the plurality of base stations whilecontrolling the transmitting power of the PDSCH according to the DPCH,an optimum value of a power ratio between the PDSCH and the DPCH isoptimized according to the position of the mobile station, and thus itis possible to maintain the receiving quality of the PDSCH at a fixedlevel regardless of the position of the mobile station on the softhandover.

[0019] In addition, as for the above-mentioned method of selecting thetransmission mode, the PDSCH that is the data channel is transmitted byjust one base station, while the transmitting power of the DPCH in thebase stations is controlled, on the soft handover when the plurality ofbase stations simultaneously transmit the DPCH to the mobile station, bythe receiving quality generated by synthesizing the received DPCHtransmitted from the plurality of base stations in the mobile station,resulting in a value different from the transmitting power in the casewhere only one base station transmits the DPCH, so that there is a faultthat it is not possible to adequately select the transmission mode ofthe PDSCH and maintain the receiving quality of the PDSCH at a fixedlevel.

[0020] Another object of the present invention is to provide thecommunication control method in the mobile communication system and thebase station and the program record medium used therefor, wherein, inthe case where the PDSCH is transmitted by one specific base station andthe DPCH is simultaneously transmitted by the plurality of base stationswhile controlling the transmission mode of the PDSCH according to thetransmitting power of the DPCH, the transmission mode of the PDSCH iscontrolled according to the position of the mobile station, and thus itis possible to maintain the receiving quality of the PDSCH at a fixedlevel regardless of the position of the mobile station on the softhandover.

[0021] According to the present invention, it is possible to acquire acommunication control method in a mobile communication system wherein amobile station and a plurality of base stations in a soft handover statewith this mobile station setting up a dedicated channel to the abovedescribed mobile station and informing a common pilot channel areincluded, and only a specific base station of the plurality of basestations in the soft handover state has a shared channel with the abovedescribed mobile station set up, the above described methodcharacterized by, in the above described mobile station, measuringreceived power of the above described dedicated channel or common pilotchannel transmitted from each of the above described plurality of basestations and notifying the above described specific base station of thismeasuring results information, and in the above described specific basestation, controlling data transmission of the above described sharedchannel based on transmitting power of the above described dedicatedchannel and the above described measuring results information, the abovedescribed controlling performed according to a ratio between a sum ofthe above described received power and the received power from the abovedescribed specific base station.

[0022] According to the present invention, it is possible to acquire thecommunication control method in the mobile communication system whereinthe mobile station and the plurality of base stations in the softhandover state with this mobile station setting up the dedicated channelto the above described mobile station and informing the common pilotchannel are included, and only the specific base station of theplurality of base stations in the soft handover state has the sharedchannel with the above described mobile station set up, the abovedescribed method characterized by, in the above described mobilestation, measuring the received power of the above described dedicatedchannel or common pilot channel transmitted from each of the abovedescribed plurality of base stations and notifying the above describedspecific base station of this measuring results information, and in theabove described specific base station, performing the data transmissionof the above described shared channel by the power determined based onthe above described measuring results information and the transmittingpower of the above described dedicated channel, and the above describeddetermined power being a value according to the ratio between the sum ofthe above described received power and the received power from the abovedescribed specific base station.

[0023] According to the present invention, it is possible to acquire thecommunication control method in the mobile communication system whereinthe mobile station and the plurality of base stations in the softhandover state with this mobile station setting up the dedicated channelto the above described mobile station and informing the common pilotchannel are included, and only the specific base station of theplurality of base stations in the soft handover state has the sharedchannel with the above described mobile station set up, the abovedescribed method characterized by, in the above described mobilestation, measuring receiving SIR (Signal to Interference Ratio) of theabove described dedicated channel or the above described common pilotchannel transmitted from each of the above described plurality of basestations and notifying the above described specific base station of thismeasuring results information, and in the above described specific basestation, controlling the data transmission of the above described sharedchannel based on the transmitting power of the above described dedicatedchannel and the above described measuring results information, and thiscontrolling performed according to the ratio between the sum of theabove described receiving SIR and the receiving SIR from the abovedescribed specific base station.

[0024] According to the present invention, it is possible to acquire thecommunication control method in the mobile communication system whereinthe mobile station and the plurality of base stations in the softhandover state with this mobile station setting up the dedicated channelto the above described mobile station and informing the common pilotchannel are included, and only the specific base station of theplurality of base stations in the soft handover state has the sharedchannel with the above described mobile station set up, the abovedescribed method characterized by, in the above described mobilestation, measuring the receiving SIR (Signal to Interference Ratio) ofthe above described dedicated channel or the above described commonpilot channel transmitted from each of the above described plurality ofbase stations and notifying the above described specific base station ofthis measuring results information, and in the above described specificbase station, performing the data transmission of the above describedshared channel by the power determined based on the above describedmeasuring results information and the transmitting power of the abovedescribed dedicated channel, and the above described determined powerbeing the value according to the ratio between the sum of the abovedescribed receiving SIR and the receiving SIR from the above describedspecific base station.

[0025] According to the present invention, it is possible to acquire thespecific base station in the mobile communication system wherein themobile station and the plurality of base stations in the soft handoverstate with this mobile station setting up the dedicated channel to theabove described mobile station and informing the common pilot channelare included, and only the specific base station of the plurality ofbase stations in the soft handover state has the shared channel with theabove described mobile station set up, the above described specific basestation characterized by, in response to the notification of themeasuring results information in the above described mobile station onthe received power of the above described dedicated channel or the abovedescribed common pilot channel transmitted from each of the abovedescribed plurality of base stations, controlling the data transmissionof the above described shared channel based on the transmitting power ofthe above described dedicated channel and the above described measuringresults information, this controlling performed according to the ratiobetween the sum of the above described received power and the receivedpower from the above described specific base station.

[0026] According to the present invention, it is possible to acquire thespecific base station in the mobile communication system wherein themobile station and the plurality of base stations in the soft handoverstate with this mobile station setting up the dedicated channel to theabove described mobile station and informing the common pilot channelare included, and only the specific base station of the plurality ofbase stations in the soft handover state has the shared channel with theabove described mobile station set up, the above described specific basestation characterized by, in response to the notification of themeasuring results information in the above described mobile station onthe received power of the above described dedicated channel or the abovedescribed common pilot channel transmitted from each of the abovedescribed plurality of base stations, performing the data transmissionof the above described shared channel by the power determined based onthis measuring results information and the transmitting power of theabove described dedicated channel, and the above described determinedpower being the value according to the ratio between the sum of theabove described received power and the received power from the abovedescribed specific base station.

[0027] According to the present invention, it is possible to acquire thespecific base station in the mobile communication system wherein themobile station and the plurality of base stations in the soft handoverstate with this mobile station setting up the dedicated channel to theabove described mobile station and informing the common pilot channelare included, and only the specific base station of the plurality ofbase stations in the soft handover state has the shared channel with theabove described mobile station set up, the above described specific basestation characterized by, in response to the notification of themeasuring results information in the above described mobile station onthe receiving SIR (Signal to Interference Ratio) of the above describeddedicated channel or the above described common pilot channeltransmitted from each of the above described plurality of base stations,controlling the data transmission of the above described shared channelbased on the transmitting power of the above described dedicated channeland the above described measuring results information, and thiscontrolling performed according to the ratio between the sum of theabove described receiving SIR and the receiving SIR from the abovedescribed specific base station.

[0028] According to the present invention, it is possible to acquire thespecific base station in the mobile communication system wherein themobile station and the plurality of base stations in the soft handoverstate with this mobile station setting up the dedicated channel to theabove described mobile station and informing the common pilot channelare included, and only the specific base station of the plurality ofbase stations in the soft hand over state has the shared channel withthe above described mobile station set up, the above described specificbase station characterized by, in response to the notification of themeasuring results information in the above described mobile station onthe receiving SIR (Signal to Interference Ratio) of the above describeddedicated channel or the above described common pilot channeltransmitted from each of the above described plurality of base stations,performing the data transmission of the above described shared channelby the power determined based on this measuring results information andthe transmitting power of the above described dedicated channel, and theabove described determined power being the value according to the ratiobetween the sum of the above described receiving SIR and the receivingSIR from the above described specific base station.

[0029] According to the present invention, it is possible to acquire arecord medium having recorded a control program of the specific basestation in the mobile communication system wherein the mobile stationand the plurality of base stations in the soft handover state with thismobile station setting up the dedicated channel to the above describedmobile station and informing the common pilot channel are included, andonly the specific base station of the plurality of base stations in thesoft handover state has the shared channel with the above describedmobile station set up, the above described program characterized by,including a process of, in response to the notification of the measuringresults information in the above described mobile station on thereceived power of the above described dedicated channel or the abovedescribed common pilot channel transmitted from each of the abovedescribed plurality of base stations, controlling the data transmissionof the above described shared channel based on the transmitting power ofthe above described dedicated channel and the above described measuringresults information, the above described controlling performed accordingto the ratio between the sum of the above described received power andthe received power from the above described specific base station.

[0030] According to the present invention, it is possible to acquire therecord medium having recorded the control program of the specific basestation in the mobile communication system wherein the mobile stationand the plurality of base stations in the soft handover state with thismobile station setting up the dedicated channel to the above describedmobile station and informing the common pilot channel are included, andonly the specific base station of the plurality of base stations in thesoft handover state has the shared channel with the above describedmobile station set up, the above described program characterized by,including the process of, in response to the notification of themeasuring results information in the above described mobile station onthe received power of the above described dedicated channel or the abovedescribed common pilot channel transmitted from each of the abovedescribed plurality of base stations, performing the data transmissionof the above described shared channel by the power determined based onthis measuring results information and the transmitting power of theabove described dedicated channel, and the above described determinedpower being the value according to the ratio between the sum of theabove described received power and the received power from the abovedescribed specific base station.

[0031] According to the present invention, it is possible to acquire therecord medium having recorded the control program of the specific basestation in the mobile communication system wherein the mobile stationand the plurality of base stations in the soft handover state with thismobile station setting up the dedicated channel to the mobile stationand informing the common pilot channel are included, and only thespecific base station of the plurality of base stations in the softhandover state has the shared channel with the above described mobilestation set up, the above described program characterized by, includingthe process of, in response to the notification of the measuring resultsinformation in the above described mobile station on the receiving SIR(Signal to Interference Ratio) of the above described dedicated channelor the above described common pilot channel transmitted from each of theabove described plurality of base stations, performing the datatransmission of the above described shared channel by the powerdetermined based on this measuring results information and thetransmitting power of the above described dedicated channel, and theabove described determined power being the value according to the ratiobetween the sum of the above described receiving SIR and the receivingSIR from the above described specific base station.

[0032] According to the present invention, it is possible to acquire acommunication control method in the mobile communication system whereinthe mobile station and the plurality of base stations in the softhandover state with this mobile station setting up the dedicated channelto the above described mobile station and informing the common pilotchannel are included, and only the specific base station of theplurality of base stations in the soft handover state has the sharedchannel with the above described mobile station set up, the abovedescribed method characterized by: in the above described mobilestation, measuring the received power of the above described dedicatedchannel or common pilot channel transmitted from each of the abovedescribed plurality of base stations and notifying the above describedspecific base station of these measuring results information, and in theabove described specific base station, determining one of the pluralityof transmission modes of different modulation or encoding methods basedon the above described measuring results information and thetransmitting power of the above described dedicated channel, andperforming data transmission of the above described shared channel inthe determined transmission mode, and the above described transmissionmode determined based on the value according to the ratio between thesum of the above described received power and the received power fromthe above described specific base station.

[0033] According to the present invention, it is possible to acquire thecommunication control method in the mobile communication system whereinthe mobile station and the plurality of base stations in the softhandover state with this mobile station setting up the dedicated channelto the above described mobile station and informing the common pilotchannel are included, and only the specific base station of theplurality of base stations in the soft handover state has the sharedchannel with the above described mobile station set up, the abovedescribed method characterized by, in the above described mobilestation, measuring the receiving SIR (Signal to Interference Ratio) ofthe above described dedicated channel or the above described commonpilot channel transmitted from each of the above described plurality ofbase stations and notifying the above described specific base station ofthese measuring results information, and in the above described specificbase station, determining one of the plurality of transmission modes ofdifferent modulation or encoding methods based on the above describedmeasuring results information and the transmitting data of the abovedescribed shared channel in the determined transmission mode, andperforming the data transmission of the above described shared channelin the determined transmission mode, and the above describedtransmission mode determined based on the value according to the ratiobetween the sum of the above described receiving SIR and the receivingSIR from the above described specific base station.

[0034] According to the present invention, it is possible to acquire thespecific base station in the mobile communication system wherein themobile station and the plurality of base stations in the soft handoverstate with this mobile station setting up the dedicated channel to theabove described mobile station and informing the common pilot channelare included, and only the specific base station of the plurality ofbase stations in the soft handover state has the shared channel with theabove described mobile station set up, the above described stationcharacterized by: in response to the notification of the measuringresults information in the above described mobile station on thereceived power of the above described dedicated channel or the abovedescribed common pilot channel transmitted from each of the abovedescribed plurality of base stations, determining one of the pluralityof transmission modes of different modulation or encoding methods basedon this measuring results information and the transmitting power of theabove described dedicated channel, and performing the data transmissionof the above described shared channel in the determined transmissionmode, and the above described transmission mode determined based on thevalue according to the ratio between the sum of the above describedreceived power and the received power from the above described specificbase station.

[0035] According to the present invention, it is possible to acquire thespecific base station in the mobile communication system wherein themobile station and the plurality of base stations in the soft handoverstate with this mobile station setting up the dedicated channel to theabove described mobile station and informing the common pilot channelare included, and only the specific base station of the plurality ofbase stations in the soft handover state has the shared channel with theabove described mobile station set up, the above described stationcharacterized by, in response to the notification of the measuringresults information in the above described mobile station on thereceiving SIR (Signal to Interference Ratio) of the above describeddedicated channel or common pilot channel transmitted from each of theabove described plurality of base stations, determining one of theplurality of transmission modes of different modulation or encodingmethods based on this measuring results information and the transmittingpower of the above described dedicated channel, and performing the datatransmission of the above described shared channel in the determinedtransmission mode, and the above described transmission mode determinedbased on the value according to the ratio between the sum of the abovedescribed receiving SIR and the receiving SIR from the above describedspecific base station.

[0036] According to the present invention, it is possible to acquire therecord medium having recorded the control program of the specific basestation in the mobile communication system wherein the mobile stationand the plurality of base stations in the soft handover state with thismobile station setting up the dedicated channel to the mobile stationand informing the common pilot channel are included, and only thespecific base station of the plurality of base stations in the softhandover state has the shared channel with the above described mobilestation set up, the above described program characterized by, includingthe process of, in response to the notification of the measuring resultsinformation in the above described mobile station on the received powerof the above described dedicated channel or the above described commonpilot channel transmitted from each of the above described plurality ofbase stations, determining one of the plurality of transmission modes ofdifferent modulation or encoding methods based on this measuring resultsinformation and the transmitting power of the above described dedicatedchannel, and performing the data transmission of the above describedshared channel in the determined transmission mode, and the abovedescribed transmission mode determined based on the value according tothe ratio between the sum of the above described received power and thereceived power from the above described specific base station.

[0037] According to the present invention, it is possible to acquire therecord medium having recorded the control program of the specific basestation in the mobile communication system wherein the mobile stationand the plurality of base stations in the soft handover state with thismobile station setting up the dedicated channel to the above describedmobile station and informing the common pilot channel are included, andonly the specific base station of the plurality of base stations in thesoft handover state has the shared channel with the above describedmobile station set up, the above described program characterized by:including the process of, in response to the notification of themeasuring results information in the above described mobile station onthe receiving SIR of the above described dedicated channel or commonpilot channel transmitted from each of the above described plurality ofbase stations, determining one of the plurality of transmission modes ofdifferent modulation or encoding methods based on this measuring resultsinformation and the transmitting power of the above described dedicatedchannel, and performing the data transmission of the above describedshared channel in the determined transmission mode, and the abovedescribed transmission mode determined based on the value according tothe ratio between the sum of the above described receiving SIR and thereceiving SIR from the above described specific base station.

[0038] In addition, the above described transmission mode may also bedetermined based on the value acquired by multiplying the transmittingpower of the above described dedicated channel by the ratio between thesum of the above described received power and the received power fromthe above described specific base station. Moreover, the above describedtransmission mode may also be determined based on the value acquired bymultiplying the transmitting power of the above described dedicatedchannel by the ratio between the sum of the above described receivingSIR and the receiving SIR from the above described specific base station

[0039] Workings of the present invention will be described. The mobilestation notifies the specific base station (the base station fortransmitting a PDSCH) of each of the above measuring results, and thespecific base station notified thereof multiplies the transmitting powerof a DPCH that is the dedicated channel transmitted by the base stationby a coefficient determined based on these measuring results so as tocontrol transmission by using that multiplication value.

[0040] To mention it further, when the transmitting power of thededicated channel is controlled so that receiving quality of the signalof the dedicated channel transmitted from one base station becomesfixed, that transmitting power reflects a propagation loss from the basestation to the mobile station and a link state of noise power andinterference wave power in the mobile station.

[0041] Accordingly, in the case of performing the data transmission byusing the shared channel from that base station, it is possible to exertcontrol reflecting the link state by controlling the data transmissionaccording to the transmitting power thereof.

[0042] However, when the transmitting power of the dedicated channel iscontrolled by synthesizing the signals of the dedicated channelstransmitted from the plurality of base stations in the mobile stationperforming the soft handover so that the receiving quality of thesynthesized signals becomes fixed, that transmitting power does notcorrectly reflect the link state from the specific base station to themobile station for performing the data transmission using the sharedchannel. It is because the receiving quality of the synthesized signalalso depends on the signals from the base stations other than thespecific base station.

[0043] According to the method of the present invention, it is possibleto exert control not only using the transmitting power of the dedicatedchannel, but also estimating a difference between the receiving qualityof the signal from the specific base station and that of the signalwherein the signals from the plurality of base stations including thespecific base station are synthesized and reflecting the link state fromthe specific base station to the mobile station by using the difference.

[0044] For that reason, even if the link state changes due to theposition of the mobile station, it is possible to maintain the linkquality of the data transmission at a fixed level and improve efficiencyof the data transmission.

[0045] To be more specific, the mobile communication system forcontrolling the transmitting power of the PDSCH controls the value ofthe ratio between the transmitting power of the PDSCH and thetransmitting power of the DPCH that is the dedicated channel so that itbecomes the ratio determined based on the measured values (receivingquality) of the received power and the receiving SIR (Signal toInterference Ratio) of the common channel or the dedicated channel inthe mobile station so as to be optimized according to the position ofthe mobile station on the soft handover in the base station fortransmitting the PDSCH that is a large-capacity shared data transmissionline.

[0046] In addition, the mobile communication system capable of selectingthe transmission mode of the PDSCH controls the transmission mode sothat the transmitting power per information bit transmitted by the PDSCHis determined based on the measured values (receiving quality) of thereceived power and the receiving SIR (Signal to Interference Ratio) ofthe common channel or the dedicated channel in the mobile station so asto be optimized according to the position of the mobile station on thesoft handover in the base station for transmitting the PDSCH that is alarge-capacity shared data transmission line.

BRIEF DESCRIPTION OF THE DRAWINGS

[0047]FIG. 1 is an simplified system diagram to which an embodiment ofthe present invention is applied;

[0048]FIG. 2 is a block diagram showing the embodiment of a mobilestation of the present invention;

[0049]FIG. 3 is a flowchart showing operation of the mobile station inFIG. 2;

[0050]FIG. 4 is a format diagram of a DPCH that is a dedicated channel;

[0051]FIG. 5 is a block diagram showing another embodiment of the mobilestation of the present invention;

[0052]FIG. 6 is a block diagram showing the embodiment of a base stationof the present invention;

[0053]FIG. 7 is a flowchart representing the operation of the basestation in FIG. 6;

[0054]FIG. 8 is a block diagram showing the embodiment of the basestation in the second embodiment of the present invention;

[0055]FIG. 9 is a flowchart representing the operation of the basestation in FIG. 8;

[0056]FIG. 10 is a diagram showing an example of the operation oftransmission mode selection in the second embodiment;

[0057]FIG. 11 is a diagram showing a concept of the transmission modeselection in the conventional example; and

[0058]FIG. 12 is a diagram showing an conventional example of theoperation of the transmission mode selection.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0059] A first embodiment of the present invention will be describedhereafter. First, a description will be made as to the case where, in acellular mobile communication system in an HSDPA mode as shown in FIG.1, a mobile station 10 is in a soft handover state with base stations 1and 2, and a PDSCH that is a large-capacity line is set up from the basestation 1 to the mobile station 10.

[0060] In the present invention, the A of the equation (1) is set as(P1+P2)/P1. Here, P1 and P2 represent received powers of CPICH 1 andCPICH 2 in the mobile station 10 respectively. Accordingly, atransmitting power of the PDSCH in the base station 1 in the presentinvention is as follows.

P _(PDSCH) =P _(DPCH1)·{(P1+P2)/P1}·C  (2)

[0061] Moreover, the C in this case is a predetermined value.

[0062] The transmitting power of the PDSCH is determined by a relationsatisfying this equation (2) so that the receiving quality of the PDSCHin the mobile station 10 will be maintained at a fixed level regardlessof a position of the mobile station 10 on the soft handover. It will beproved hereafter.

[0063] Now, if a propagation loss from the base station 1 to the mobilestation 10 is L1, the propagation loss from the base station 2 to themobile station 10 is L2, and an interference wave (disturbing wave) isI, a ratio between a signal transmitted from the base station 1 in therelation of the equation (2) and interference wave power is as followsin the mobile station 10. $\begin{matrix}{\frac{P_{PDSCH}}{L_{1} \cdot I} = {\frac{P_{DPCH1}}{L_{1} \cdot I} \cdot \frac{P_{1} + P_{2}}{P_{1}} \cdot C}} & (3)\end{matrix}$

[0064] In the equation (3), if P_(PDSCH)/L₁ is S_(PDSCH), andP_(DPCH1)/L₁, is S₁), it will be as follows. $\begin{matrix}{\frac{S_{PDSCH}}{I} = {\frac{S_{1}}{I} \cdot \frac{P_{1} + P_{2}}{P_{1}} \cdot C}} & (4)\end{matrix}$

[0065] Now, the transmitting powers of a DPCH 1 and a DPCH 2 in the basestations are con-trolled by a high-speed power control loop so that thereceiving quality of the signals after synthesis becomes fixed. To bemore specific, the mobile station synthesizes the signals of the DPCH 1and the DPCH 2 and compares the receiving quality of the synthesizedsignals to a fixed desired value, and according to the results thereof,it notifies the base station of a command for giving an instruction forincreasing or decreasing the transmitting powers, so that each basestation increases or decreases the transmitting power of the DPCH 1 andthe DPCH 2 according to the notification. Each base station rendersinitial values of the transmitting powers fixed, and increases ordecreases the transmitting powers according to the same command from themobile station, and so both the transmitting powers are balanced andaccordingly transmitting powers P_(d1), and P_(d2) are equal as follows.

P_(d1)=P_(d2)=P_(d)  (5)

[0066] In addition, transmitting powers P_(c1) and P_(c2) of the CPICH 1and the CPICH 2 are fixed, and a transmitting power ratio of CPICH/DPCHin the base station 1 and 2 are mutually equal.

[0067] Accordingly, it is as follows.

P_(c1)/P_(d1)=P_(c2)/P_(d2)  (6)

[0068] And from the equation (5), it is as follows.

P_(c1)/P_(d)=P_(c2)/P_(d)  (7)

[0069] And so it is as follows.

P_(c1)=P_(c2)(P_(c))  (8)

[0070] Accordingly, the equation (4) can be rewritten as follows.$\begin{matrix}\begin{matrix}{\frac{S_{PDSCH}}{I} = {\frac{S_{1}}{I} \cdot \frac{\frac{P_{c}}{L_{1}} + \frac{P_{c}}{L_{2}}}{\frac{P_{C}}{L_{1}}} \cdot C}} \\{= {\frac{S_{1}}{I} \cdot \frac{\frac{1}{L_{1}} + \frac{1}{L_{2}}}{\frac{1}{L_{1}}} \cdot C}} \\{= {\frac{S_{1}}{I} \cdot \frac{\frac{P_{d}}{L_{1}} + \frac{P_{d}}{L_{2}}}{\frac{P_{d}}{L_{1}}} \cdot C}}\end{matrix} & (9)\end{matrix}$

[0071] Furthermore, if the equation (9) is rewritten by using theequation (5), the following can be acquired. $\begin{matrix}\begin{matrix}{\frac{S_{PDSCH}}{I} = {\frac{S_{1}}{I} \cdot \frac{\frac{P_{d1}}{L_{1}} + \frac{P_{d2}}{L_{2}}}{\frac{P_{d1}}{L_{1}}} \cdot C}} \\{= {\frac{S_{1}}{I} \cdot \frac{S_{1} + S_{2}}{S_{1}} \cdot C}} \\{= {\frac{S_{1}}{I} \cdot \frac{\frac{S_{1}}{I} + \frac{S_{2}}{I}}{\frac{S_{1}}{I}} \cdot C}} \\{= {\left( {\frac{S_{1}}{I} + \frac{S_{2}}{I}} \right) \cdot C}}\end{matrix} & (10)\end{matrix}$

[0072] The inside of the parenthesis on the right side of the equation(10) is a sum of signal to interference ratios of receiving signals ofthe DPCH 1 and the DPCH 2, representing the signal to interference ratioof the signals after synthesizing the receiving signals at a maximumratio, that is, the receiving quality of the synthesized signals, whichis kept fixed by the high-speed power control loop so that, as revealed,the receiving quality of the PDSCH in the mobile station shown in theequation (3) consequently becomes fixed.

[0073] Accordingly, the received powers P1 and P2 of the CPICH 1 and theCPICH 2 of the base station 1 and 2 in the soft handover relation shouldbe measured in the mobile station 10 with the measuring results notifiedto the base station 1, where the P1 and P2 should be used to calculatethe transmitting power of the PDSCH from the equation (2) so as totransmit data to the large-capacity line.

[0074] While the received powers of the CPICH 1 and the CPICH 2 aremeasured in the mobile station 10 in the above example, it is alsofeasible to measure the received powers of individual pilot signals ofthe DPCH 1 and the DPCH 2 instead and use them as the above P1 and P2.In this case, the equation in the second line of the equation (10) isimmediately acquired from the equation (4) and the equation in the lastline of the equation (10) also follows, so that the effect exactly thesame as using the received power of the CPICH can be obtained.

[0075] Moreover, while the condition shown in the equation (5), that is,the condition that the transmitting powers P_(d1) and P_(d2) of the DPCH1 and the DPCH 2 are equal is required in the case of using the receivedpowers of the CPICH, the equation (10) holds without the above conditionin the case of using the DPCH.

[0076] While the mobile station 10 notifies the base station 1 of thereceived power measured values P1 and P2, it may also notify P2/P1,P1/P2, (P1+P2)/P1, P1/(P1+P2) and so on or an average thereof in asection of a predetermined number of frames. Furthermore, it is alsofeasible to receive the P1 and P2 on the base station side to calculateand average the above values.

[0077] Furthermore, it is also possible to use the value of A by raisingit to the αth power, in which case it is equivalent to multiplying adecibel value by an integer. In addition, it is also possible to setupper and lower limits to the A.

[0078]FIG. 2 is a block diagram of the embodiment of the mobile stationof the present invention, and FIG. 3 is a simplified operation flowchartthereof. A received wave from an antenna 11 is supplied to a receptionportion 13 via a duplexer (DUP) 12 and is demodulated. The demodulationoutput is separated into user information and control information by achannel separation portion 14. Among the control information, commonpilot channels CPICHs are detected by detection portions 15 and 16respectively, and the received powers P1 and P2 are measured in powermeasurement portions 17 and 18 (step S1).

[0079] These measured values P1 and P2 are supplied to a notifyinginformation generation portion 19, where notifying information to thebase station 1 is generated (step S2).

[0080] This notifying information generation portion 19 generates anyone of the ratio between the sum of the received powers of the signalsfrom the plurality of base stations 1 and 2 and the received power ofthe signals from a specific base station, the ratio between the sum ofthe received powers of the signals from the plurality of base stationsexcept the specific base station and the received power of the signalsfrom the specific base station, and inverse numbers of the seratios. Tobe more specific, it generates P1/P2, P2/P1, (P1+P2)/P1, P1/(P1+P2) orthe average values of these several frames as the notifying informationbased on the measured values P1 and P2. This notifying information issynthesized with transmitting information in a synthesis portion 20, andis applied to a transmission portion 21 to be modulated so that it istransmitted to the base station 1 via the DUP 12 (step S3).

[0081] The notifying information at this time is transmitted by using anuplink of the DPCH 1. FIG. 4 shows a format of the DPCH, where theuplink and downlink are different. The uplink DPCH is comprised of aDPCCH (Dedicated Physical Control Channel) and a DPDCH (DedicatedPhysical Data Channel), and they are orthogonally modulated mutually.The DPCCH has pilot signals (dedicated), transmission power controlinformation (TPC), feedback information (FBI) and communication data.While this FBI includes a CW (code word: specifying a primary basestation) used for SSDT (site selection diversity transmission: a modewherein only the base station having the highest (primary) receivedpower of the CPICH in the mobile station performs data transmission),the system of the present invention does not adopt the SSDT mode so thatthis CW portion may be used for the above-mentioned notifyinginformation. In addition, it is a matter of course that anotheravailable bit may be used.

[0082]FIG. 5 is a block diagram of another embodiment of the mobilestation of the present invention, and the portions equal to those inFIG. 2 are indicated by the same symbols. In this example, the DPCH ismeasured instead of the CPICH, and so the only difference is that theportions 15 and 16 for measuring the CPICH in FIG. 2 are the portions 22and 23 for measuring the DPCH.

[0083]FIG. 6 is a block diagram of the embodiment of the base station ofthe present invention, and FIG. 7 is a rough operation flowchartthereof. The received wave from an antenna 31 is inputted to a receptionportion 33 via a DUP 32 and is demodulated. As for demodulation output,the DPCH is detected in a DPCH detection portion 34, and the notifyinginformation from the mobile station included therein is detected by anotifying information detection portion 35 (step S11).

[0084] This notifying information is inputted to a transmitting powerdetermination portion 36 and controls gain of a transmission amplifier37 so that the transmitting power of the PDSCH becomes the equation (2).To be more specific, a multiplication coefficient (P1+P2)/P1 for thetransmitting power of the DPCH not shown is generated, and control isperformed by multiplying the transmitting power of the DPCH by thiscoefficient (step S12), and it is modulated by a transmission portion 38so that the PDSCH is transmitted to the mobile station (step S13).Moreover, the CPICH and the DPCH are omitted in FIG. 6.

[0085] While a control amount of the transmitting power is determined byusing the received powers of the CPICH and the DPCH in the mobilestation in the above-mentioned embodiment, it can be implemented just inthe same way by using a SIR (Signal to Interference Ratio) of the CPICHand the DPCH.

[0086] In addition, while a description was made as to the case wherethe number of the base stations on the soft handover is two, it applieslikewise to the cases where it is three or more, in which cases thevalue (coefficient) of the A in the equation (2) is (P1+P2+P3+. . .)/P1.

[0087] It is evident that the flow in FIG. 7 for controlling operationof the base station can be implemented by recording a program on arecord medium and reading it to control the operation of hardware (acomputer).

[0088] In the above embodiment, while an example of controlling thetransmitting power is shown as a method of controlling the datatransmission by using a shared channel, there is also the method ofcontrolling the data transmission wherein a modulation method or anencoding method is changed according to a link state while maintaining afixed transmitting power, and the present invention is also applicableto such control.

[0089] Furthermore, another embodiment (a second embodiment) of thepresent invention will be described. As in the embodiment describedearlier, a description will be made as to the case where, in thecellular mobile communication system in the HSDPA mode as shown in FIG.1, the mobile station 10 is in the soft handover state with basestations 1 and 2, and the PDSCH that is the large-capacity line is setup from the base station 1 to the mobile station 10. The base station 1transmits the CPICH 1 and the PDSCH, and transmits and receives the DPCH1 to and from the mobile station 10, and the base station 2 transmitsthe CPICH 2, and transmits and receives the DPCH 2 to and from themobile station 10. In addition, it is the same as the embodimentdescribed earlier in that the mobile station 10 measures the receivedpowers P1 and P2 of the CPICH 1 and the CPICH 2 respectively andnotifies the base stations of the information thereon, and in that thetransmitting power of the downlink DPCH is controlled by the commandnotified by the mobile station for giving the instruction for increasingor decreasing the transmitting power.

[0090] In the mobile communication system of the second embodiment, itis possible to select a plurality of transmission modes using modulationmethods such as QPSK (Quadrature Phase Shift Keying) capable oftransmitting 2 bits (4 values) by 1 symbol, 16 QAM (16 QuadratureAmplitude Modulation) capable of transmitting 4 bits (16 values) by 1symbol, 64 QAM (64 Quadrature Amplitude Modulation) capable oftransmitting 6 bits (64 values) by 1 symbol and so on. The number ofsymbols to be transmitted per second is fixed regardless of thetransmission mode. A determination of switching the above transmissionmodes is made by the base station 1. While these transmission modes mayhave encoding rates with different encoding methods, it is fixed here asthe encoding rate of 1/3 for instance in order to simplify thedescription.

[0091] On determination of switching the above transmission modes, thebase station notifies the mobile station 2 by using the downlink (DL)DPCH (Dedicated Physical Channel), and switches the transmission modesin predetermined timing after the notification thereof, and the mobilestation 2 switches the reception modes in the same timing to receive thePDSCH transmitted by the base station.

[0092] In the determination of the transmission mode, the base stationselects the transmission mode using the modulation method according tolargeness of the multiplication value calculated by multiplying thetransmitting power P_(DPCH1) by the coefficient A as shown in FIG. 10.Here, the coefficient A is set as (P1+P2)/P1. This coefficient A is thesame as coefficient A in the preceding embodiment.

[0093] In FIG. 10, the larger each threshold is, the easier it becomesto use multi-valued modulation such as 64 QAM resulting in a higher biterror rate, so that the threshold of an upper limit of themultiplication value using the 64 QAM, for instance, is set at the valuewherein, when the multiplication value is equal to the threshold of theupper limit of the 64 QAM, the bit error rate nearly becomes the desiredvalue at the 64 QAM. In addition, the threshold of an upper limit of themultiplication value using the 16 QAM is also set likewise at the valuewherein the bit error rate nearly becomes the desired value for the 16QAM when the multiplication value is equal to the threshold of the upperlimit of the 16 QAM. Moreover, it is relatively easy to determine thethresholds by performing it on condition of A=1 without performing thesoft handover since it is not necessary to calculate the value of the A.

[0094] Thus, transmission mode power of the PDSCH is determined by thelargeness of the multiplication value so that the receiving quality ofthe PDSCH in the mobile station 10 is maintained nearly at a fixed levelregardless of the position of the mobile station 10 on the softhandover. The reason for this will be described hereafter.

[0095] In general, it is possible to render the error rate of aninformation bit as the desired value by maintaining the ratio between areceived power per information bit Eb and a noise power including aninterference power No (Eb/No) nearly at a predetermined value. As thisembodiment has the encoding rate of the transmission modes fixed, and italso has the transmitting power fixed, that is the transmitting powerper symbol fixed, the received power per bit at the 16 QAM of 4 bits by1 symbol is 1/2, and the received power per bit at the 64 QAM of 6 bitsby 1 symbol is 1/3 if a propagation path is fixed, compared with thecase of selecting the QPSK of 2 bits by 1 symbol.

[0096] Accordingly, if the propagation path is fixed, the Eb/No per bitis 1/2 at the 16 QAM and it is 1/3 at the 64 QAM compared with the caseof selecting the QPSK.

[0097] Here, the case where only one base station is transmitting theDPCH to the mobile station is considered first. The transmitting powerof the downlink DPCH is controlled so that the receiving quality of theDPCH in the mobile station becomes fixed. In addition, the propagationpaths of the DPCH and the PDSCH are the same. For this reason, when thestate of the propagation path of the PDSCH changes and the transmittingpower of the DPCH becomes 1/2 or 1/3 of the transmitting power of acertain criterion, the Eb and No of the PDSCH becomes twice or threetimes thereof respectively if the transmission mode remains fixed.Moreover, causes of this change of the condition of the propagationpaths include decrease in the propagation loss and the decrease in thenoise power including the interference power.

[0098] Accordingly, if the 16 QAM or the 64 QAM is selected as thetransmitting power of the DPCH becomes 1/2 and 1/3 when using the QPSKat the transmitting power of a certain criterion, it results inincreasing an improvement of the Eb/No due to the change by the numberof bits per symbol even if the state of the propagation path changes,leading to maintaining the Eb/No nearly at a fixed level with noincrease therein and also keeping the bit error rate nearly fixed.

[0099] Next, the case where the two base stations 1 and 2 aretransmitting the DPCHs to the mobile station 10. The transmitting powersof the DPCH 1 and the DPCH 2 are balanced, and these receiving signalsare synthesized at a maximum ratio in the mobile station. In addition,the transmitting power ratio of the CPICH and the DPCH in the basestations 1 and 2 are mutually equal. At this time, if the transmittingpower of the DPCH is k times as much as that of the CPICH, the receivedpower of the DPCH 1 is kP1 and the received power of the DPCH 2 is kP2,and so the received power of the DPCH 1 and the DPCH 2 after thesynthesis is kP1+kP2.

[0100] Accordingly, even if the base station 2 transmits the DPCH 2 tothe mobile station, the received power becomes (P1+P2) /P1 times as muchas the received power kP1 in the case of only the DPCH 1 unless thetransmitting power of the DPCH 1 is changed. However, as thetransmitting power is controlled so that the receiving quality of theDPCHs after the synthesis becomes fixed, the transmitting powers of theDPCH l and the DPCH 2 become P1/(P1+P2) times as compared with the casewhere the DPCH 2 is not transmitted.

[0101] Accordingly, the transmitting power in the case where only onebase station transmits the DPCH is acquired by multiplying by (P1+P2)/P1the transmitting power in the case where two base stations transmit theDPCHs. In the present invention, this (P1+P2)/P1 is used as thecoefficient A to multiply the transmitting power of the DPCH thereby,and the transmission mode is determined based on that multiplicationvalue so that, even in the case of performing the soft handover, thetransmission mode not affected thereby, maintaining the Eb/No nearly atthe fixed level and keeping the bit error rate nearly fixed is selected.

[0102] Accordingly, in the mobile station 10, the received powers P1 andP2 of the CPICH 1 and the CPICH 2 of the base station 1 and 2 in thesoft handover relation should be measured with the measuring resultsnotified to the base station 1, where the P1 and P2 should be used todetermine the transmission mode of the PDSCH so as to transmit data tothe large-capacity line.

[0103] While the mobile station 10 notifies the base station 1 of thereceived power measured values P1 and P2, it may also notify P2/P1,P1/P2, (P1+P2)/P1, P1/(P1+P2) and so on or an average thereof in thesection of the predetermined number of frames. Furthermore, it is alsofeasible to receive the P1 and P2 on the base station side to calculateand average the above values. Furthermore, it is also possible to usethe value of A by raising it to the αth power, in which case it isequivalent to multiplying the decibel value by the integer. In addition,it is also possible to set the upper and lower limits to the A.

[0104] While the mobile station requires a function of receiving theplurality of transmission modes in a receiver thereof, it is the same asthe first embodiment otherwise and the method of transmitting thenotifying information from the mobile station to the base station isalso the same, and so the description thereof is omitted.

[0105]FIG. 8 is a block diagram of the embodiment of the base station ofthe present invention, and FIG. 9 is a rough operation flowchartthereof. The receiving signal from the antenna 31 is inputted to thereception portion 33 via the duplexer DUP 32 and is demodulated. As forthe demodulation output, the DPCH is detected in the DPCH detectionportion 34, and the notifying information from the mobile stationincluded therein is detected by the notifying information detectionportion 35 (step S21).

[0106] This notifying information is inputted to the transmitting powerdetermination portion 36, and the transmitting power of the downlinkDPCH is determined according to the command giving the instruction forincreasing or decreasing the transmitting power so as to control thegain of the transmission amplifier 37 by the determined transmittingpower (step S22). In addition, the determined transmitting power isinputted to a transmission mode determination portion 39, and on theother hand, the information on the received powers of the CPICH 1 andthe CPICH 2 in the mobile station 10 included in the notifyinginformation detected by the notifying information detection portion 35is also inputted to the transmission mode determination portion 39.

[0107] And the transmission mode determination portion 39 determines thetransmission mode of a transmission mode setting portion 40 based onsuch input information so that the Eb/No in the mobile station becomesnearly fixed. To be more specific, the multiplication coefficient A thatis (P1+P2)/P1 for the transmitting power of the DPCH is generated andcontrol is exerted to multiply the transmitting power of the DPCH bythis coefficient so that, as shown in FIG. 10, the transmission modecorresponding to the modulation method is determined according to thelargeness of that multiplication value (step S23), and the PDSCH ismodulated in the transmission mode determined by the transmissionportion 38 and transmitted to the mobile station, and the DPCH amplifiedby the transmission amplifier 37 is also transmitted to the mobilestation (step S24).

[0108] Moreover, in FIG. 8, reference numeral 41 denotes transmissioninformation, and the CPICH is omitted. In addition, it is evident herethat, instead of multiplying the transmitting power by the coefficient,the decibel values of the transmitting power and that of the coefficientmay be calculated to get the sum thereof.

[0109] While the transmission mode is determined by using the receivedpowers of the CPICH and the DPCH in the mobile station in the embodimentdescribed above, it can be implemented just in the same way by using theSIR (Signal to Interference Ratio) of the CPICH and the DPCH. Inaddition, while a description was made as to the case where themodulation method is different according to the transmission mode, itcan also be implemented just in the same way in the case where theencoding method is different according to the transmission mode.

[0110] In addition, while a description was made as to the case wherethe number of the base stations on the soft handover is two, it alsoapplies likewise to the cases where it is three or more, in which casesthe value (coefficient) of the A is (P1+P2+P3+. . . )/P1.

[0111] It is evident that the flow in FIG. 9 for controlling theoperation of the base station can be implemented by recording theprogram on the record medium and reading it to control the operation ofthe hardware (computer).

[0112] As described above, according to the present invention, thereceived powers and the receiving SIR of the CPICH and the DPCH from thebase station in the soft handover state with the mobile station aremeasured on the soft handover, which are notified to the base station,and the notified base station determines the transmitting power or thetransmission mode of the shared channel based on these measured values,so that it is possible to perform data transmission by the PDSCH of theconstantly fixed quality regardless of the position of the mobilestation, and so it has the effect of improving efficiency of the datatransmission.

What is claimed is:
 1. A communication control method in a mobilecommunication system wherein a mobile station and a plurality of basestations in a soft handover state with this mobile station setting up adedicated channel to said mobile station and informing a common pilotchannel are included, and only a specific base station of the pluralityof base stations in the soft handover state has a shared channel withsaid mobile station set up, said method comprising: in said mobilestation, measuring received power of said dedicated channel or commonpilot channel transmitted from each of said plurality of base stationsand notifying said specific base station of these measuring resultsinformation; and in said specific base station, controlling datatransmission of said shared channel based on a transmitting power ofsaid dedicated channel and said measuring results information, saidcontrolling being performed according to a ratio between sum of saidreceived power and the received power from said specific base station.2. A communication control method in a mobile communication systemwherein a mobile station and a plurality of base stations in a softhandover state with this mobile station setting up a dedicated channelto said mobile station and informing a common pilot channel areincluded, and only a specific base station of the plurality of basestations in the soft handover state has a shared channel with saidmobile station set up, said method comprising: in said mobile station,measuring received power of said dedicated channel or common pilotchannel transmitted from each of said plurality of base stations andnotifying said specific base station of these measuring resultsinformation; and in said specific base station, performing datatransmission of said shared channel by a power determined based on saidmeasuring results information and a transmitting power of said dedicatedchannel, said determined power being a value according to a ratiobetween a sum of said received power and the received power from saidspecific base station.
 3. The communication control method according toclaim 2, wherein said determined power is a value acquired bymultiplying the transmitting power of said dedicated channel by theratio between the sum of said received power and the received power fromsaid specific base station.
 4. A communication control method in amobile communication system wherein a mobile station and a plurality ofbase stations in a soft handover state with this mobile station settingup a dedicated channel to said mobile station and informing a commonpilot channel are included, and only a specific base station of theplurality of base stations in the soft handover state has a sharedchannel with said mobile station set up, said method comprising: in saidmobile station, measuring a receiving SIR (Signal to Interference Ratio)of said dedicated channel or said common pilot channel transmitted fromeach of said plurality of base stations and notifying said specific basestation of these measuring results information; and in said specificbase station, controlling data transmission of said shared channel basedon a transmitting power of said dedicated channel and said measuringresults information, this controlling being performed according to theratio between a sum of the receiving SIR and the receiving SIR from saidspecific base station.
 5. A communication control method in a mobilecommunication system wherein a mobile station and a plurality of basestations in a soft handover state with this mobile station setting up adedicated channel to said mobile station and informing a common pilotchannel are included, and only a specific base station of the pluralityof base stations in the soft handover state has a shared channel withsaid mobile station set up, said method comprising: in said mobilestation, measuring a receiving SIR (Signal to Interference Ratio) ofsaid dedicated channel or said common pilot channel transmitted fromeach of said plurality of base stations and notifying said specific basestation of these measuring results information; and in said specificbase station, performing data transmission of said shared channel by apower determined based on said measuring results information and atransmitting power of said dedicated channel, said determined powerbeing a value according to a ratio between a sum of said receiving SIRand the receiving SIR from said specific base station.
 6. Thecommunication control method according to claim 5, wherein saiddetermined power is a value acquired by multiplying the transmittingpower of said dedicated channel by the ratio between the sum of saidreceiving SIR and the receiving SIR from said specific base station. 7.A specific base station in a mobile communication system wherein amobile station and a plurality of base stations in a soft handover statewith this mobile station setting up a dedicated channel to said mobilestation and informing a common pilot channel are included, and only aspecific base station of the plurality of base stations in the softhandover state has a shared channel with said mobile station set up,wherein said station, in response to notification of measuring resultsinformation in said mobile station on a received power of said dedicatedchannel or said common pilot channel transmitted from each of saidplurality of base stations, controlling data transmission of said sharedchannel based on transmitting power of said dedicated channel and saidmeasuring results information, and said controlling is performedaccording to a ratio between a sum of said received power and thereceived power from said specific base station.
 8. A specific basestation in a mobile communication system wherein a mobile station and aplurality of base stations in a soft handover state with this mobilestation setting up a dedicated channel to said mobile station andinforming a common pilot channel are included, and only the specificbase station of the plurality of base stations in the soft handoverstate has a shared channel with said mobile station set up, wherein saidspecific base station, in response to notification of measuring resultsinformation in said mobile station on a received power of said dedicatedchannel or said common pilot channel transmitted from each of saidplurality of base stations, performs data transmission of said sharedchannel by a power determined based on said measuring resultsinformation and a transmitting power of said dedicated channel, and saiddetermined power is a value according to a ratio between a sum of saidreceived power and the received power from said specific base station.9. The base station according to claim 8, wherein said determined poweris a value acquired by multiplying the transmitting power of saiddedicated channel by the ratio between the sum of said received powerand the received power from said specific base station.
 10. A specificbase station in a mobile communication system wherein a mobile stationand a plurality of base stations in a soft handover state with thismobile station setting up a dedicated channel to said mobile station andinforming a common pilot channel are included, and only the specificbase station of the plurality of base stations in the soft handoverstate has a shared channel with said mobile station set up, wherein saidspecific base station, in response to notification of measuring resultsinformation in said mobile station on a receiving SIR (Signal toInterference Ratio) of said dedicated channel or said common pilotchannel transmitted from each of said plurality of base stations,controls data transmission of said shared channel based on transmittingpower of said dedicated channel and said measuring results information,and this controlling is performed according to the ratio between a sumof said receiving SIR and the receiving SIR from said specific basestation.
 11. A specific base station in a mobile communication systemwherein a mobile station and a plurality of base stations in a softhandover state with this mobile station setting up a dedicated channelto said mobile station and informing a common pilot channel areincluded, and only the specific base station of the plurality of basestations in the soft handover state has a shared channel with saidmobile station set up, wherein said specific base station, in responseto notification of measuring results information in said mobile stationon a receiving SIR (Signal to Interference Ratio) of said dedicatedchannel or said common pilot channel transmitted from each of saidplurality of base stations, performs data transmission of said sharedchannel by a power determined based on this measuring resultsinformation and a transmitting power of said dedicated channel, and saiddetermined power is a value according to a ratio between a sum of saidreceiving SIR and the receiving SIR from said specific base station. 12.The base station according to claim 11, wherein said determined power isa value acquired by multiplying the transmitting power of said dedicatedchannel by the ratio between the sum of said receiving SIR and thereceiving SIR from said specific base station.
 13. A record mediumhaving recorded a control program of a specific base station in a mobilecommunication system wherein a mobile station and a plurality of basestations in a soft handover state with this mobile station setting up adedicated channel to said mobile station and informing a common pilotchannel are included, and only a specific base station of the pluralityof base stations in the soft handover state has a shared channel withsaid mobile station set up, said program including a process of: inresponse to notification of measuring results information in said mobilestation on a received power of said dedicated channel or said commonpilot channel transmitted from each of said plurality of base stations,controlling data transmission of said shared channel based ontransmitting power of said dedicated channel and said measuring resultsinformation, said controlling being performed according to a ratiobetween a sum of said received power and the received power from saidspecific base station.
 14. A record medium having recorded a controlprogram of a specific base station in a mobile communication systemwherein a mobile station and a plurality of base stations in a softhandover state with this mobile station setting up a dedicated channelto said mobile station and informing a common pilot channel areincluded, and only a specific base station of the plurality of basestations in the soft handover state has a shared channel with saidmobile station set up, said program including a process of: in responseto notification of measuring results information in said mobile stationon a received power of said dedicated channel or said common pilotchannel transmitted from each of said plurality of base stations,performing data transmission of said shared channel by a powerdetermined based on said measuring results information and atransmitting power of said dedicated channel, said determined powerbeing a value according to a ratio between a sum of said received powerand the received power from said specific base station.
 15. A recordmedium having recorded a control program of a specific base station in amobile communication system wherein a mobile station and a plurality ofbase stations in a soft handover state with this mobile station settingup a dedicated channel to the mobile station and informing a commonpilot channel are included, and only a specific base station of theplurality of base stations in the soft handover state has a sharedchannel with said mobile station set up, said program including aprocess of: in response to notification of measuring results informationin said mobile station on a receiving SIR (Signal to Interference Ratio)of said dedicated channel or said common pilot channel transmitted fromeach of said plurality of base stations, performing data transmission ofsaid shared channel by a power determined based on this measuringresults information and a transmitting power of said dedicated channel,said determined power being a value according to a ratio between a sumof said receiving SIR and the receiving SIR from said specific basestation.
 16. A communication control method in a mobile communicationsystem wherein a mobile station and a plurality of base stations in asoft handover state with this mobile station setting up a dedicatedchannel to said mobile station and informing a common pilot channel areincluded, and only a specific base station of the plurality of basestations in the soft handover state has a shared channel with saidmobile station set up, said method comprising: in said mobile station,measuring received power of said dedicated channel or common pilotchannel transmitted from each of said plurality of base stations andnotifying said specific base station of these measuring results; and insaid specific base station, determining one of a plurality oftransmission modes of different modulation or encoding methods based onsaid measuring results information and transmitting power of saiddedicated channel, and performing data transmission of said sharedchannel in the determined transmission mode, said transmission modebeing determined based on a value according to a ratio between a sum ofsaid received power and the received power from said specific basestation.
 17. A communication control method in a mobile communicationsystem wherein a mobile station and a plurality of base stations in asoft handover state with this mobile station setting up a dedicatedchannel to said mobile station and informing a common pilot channel areincluded, and only a specific base station of the plurality of basestations in the soft handover state has a shared channel with saidmobile station set up, said method comprising: in said mobile station,measuring a receiving SIR (Signal to Interference Ratio) of saiddedicated channel or said common pilot channel transmitted from each ofsaid plurality of base stations and notifying said specific base stationof these measuring results; and in said specific base station,determining one of a plurality of transmission modes of differentmodulation or encoding methods based on said measuring resultsinformation and transmitting power of said dedicated channel, andperforming data transmission of said shared channel in the determinedtransmission mode, said transmission mode being determined based on avalue according to a ratio between a sum of said receiving SIR and thereceiving SIR from said specific base station.
 18. A specific basestation in a mobile communication system wherein a mobile station and aplurality of base stations in a soft handover state with this mobilestation setting up a dedicated channel to said mobile station andinforming a common pilot channel are included, and only the specificbase station of the plurality of base stations in the soft handoverstate has a shared channel with said mobile station set up, wherein saidspecific base station, in response to notification of measuring resultsinformation in said mobile station on a received power of said dedicatedchannel or said common pilot channel transmitted from each of saidplurality of base stations, determines one of a plurality oftransmission modes of different modulation or encoding methods based onthis measuring results information and transmitting power of saiddedicated channel, and performs data transmission of said shared channelin the determined transmission mode, and said transmission mode isdetermined based on a value according to a ratio between a sum of saidreceived power and the received power from said specific base station.19. A specific base station in a mobile communication system wherein amobile station and a plurality of base stations in a soft handover statewith this mobile station setting up a dedicated channel to said mobilestation and informing a common pilot channel are included, and only thespecific base station of the plurality of base stations in the softhandover state has a shared channel with said mobile station set up,wherein said specific base station, in response to notification ofmeasuring results information in said mobile station on a receiving SIR(Signal to Interference Ratio) of said dedicated channel or common pilotchannel transmitted from each of said plurality of base stations,determines one of a plurality of transmission modes of differentmodulation or encoding methods based on this measuring resultsinformation and transmitting power of said dedicated channel, andperforms data transmission of said shared channel in the determinedtransmission mode, and said transmission mode is determined based on avalue according to a ratio between a sum of said receiving SIR and thereceiving SIR from said specific base station.
 20. A record mediumhaving recorded a control program of a specific base station in a mobilecommunication system wherein a mobile station and a plurality of basestations in a soft handover state with this mobile station setting up adedicated channel to the mobile station and informing a common pilotchannel are included, and only a specific base station of the pluralityof base stations in the soft handover state has a shared channel withsaid mobile station set up, said program including a process of: inresponse to notification of measuring results information in said mobilestation on a received power of said dedicated channel or said commonpilot channel transmitted from each of said plurality of base stations,determining one of a plurality of transmission modes of differentmodulation or encoding methods based on this measuring resultsinformation and transmitting power of said dedicated channel, andperforming data transmission of said shared channel in the determinedtransmission mode, said transmission mode being determined based on avalue according to a ratio between a sum of said received power and thereceived power from said specific base station.
 21. A record mediumhaving recorded a control program of a specific base station in a mobilecommunication system wherein a mobile station and a plurality of basestations in a soft handover state with this mobile station setting up adedicated channel to said mobile station and informing a common pilotchannel are included, and only a specific base station of the pluralityof base stations in the soft handover state has a shared channel withsaid mobile station set up, said program including a process of: inresponse to notification of measuring results information in said mobilestation on a receiving SRI of said dedicated channel or common pilotchannel transmitted from each of said plurality of base stations,determining one of a plurality of transmission modes of differentmodulation or encoding methods based on this measuring resultsinformation and transmitting power of said dedicated channel, andperforming data transmission of said shared channel in the determinedtransmission mode, said transmission mode being determined based on avalue according to a ratio between a sum of said receiving SIR and thereceiving SIR from said specific base station.